1. Field of the Invention
The present invention relates generally to pedal mechanisms for powering machinery, and more specifically to an infinitesimally adjustable reciprocating pedal drive mechanism for powering a mobile vehicle or stationary device, such as a bicycle or exercise bicycle. The present mechanism allows the stroke of each pedal to be adjusted, as well as providing for the adjustment of the effective gear ratios of the pedal mechanism as desired. A stand for supporting a bicycle equipped with the present pedal drive mechanism, enabling the bicycle to be used as an exercise bike, is also provided.
2. Description of the Related Art
The so-called xe2x80x9csafety bicycle,xe2x80x9d incorporating front and rear wheels of generally equal diameters and a pedal mechanism including an increase in the effective drive ratio between pedals and drive wheel, was considered a significant advance in the bicycle industry when it was developed in the late nineteenth century. This mechanism provided the speed desired, without necessitating an extremely large drive wheel with its accompanying direct pedal drive, as in the xe2x80x9cordinaryxe2x80x9d type of bicycle.
However, it has long been recognized that additional improvements in the pedal and chain sprocket drive mechanism of the conventional bicycle, are desirable. For one thing, the circular motion of the pedals in a conventional bicycle pedal drive mechanism are not optimally efficient for receiving power from the generally reciprocating motion provided by the legs of a rider. Another problem is the provision of finite gear ratios in such bicycles, which cannot provide optimum ratios under every circumstance. Even where those ratios are close to optimum, such geared bicycles cannot provide variable pedal positions to optimize the leg thrust or force of a rider, nor can they vary the pedal stroke in order to optimize the leg force further. This is true for both mobile bicycles and also for stationary exercise bicycles or exercise mechanisms using a pedal-like arrangement.
Accordingly, a need will be seen for an adjustable pedal mechanism for mobile and stationary vehicles, particularly for bicycles and the like. The mechanism must provide a reciprocating action for the pedals, in order to simulate more closely the natural reciprocating action of the legs of an individual while walking or running. Moreover, the mechanism must provide for the adjustment of the pedal stroke as required, as well as for positioning the mechanism at least arcuately as desired to further optimize the energy of the rider. Finally, the mechanism must also provide an infinitesimally adjustable ratio in order to optimize the energy of the rider even further.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 4,019,230 issued on Apr. 26, 1977 to Melville R. Pollard, titled xe2x80x9cReciprocating Powered Bicycle,xe2x80x9d describes a bicycle having conventional drive and driven sprockets with a continuously rotating chain extending therearound. However, the pedal arms are not affixed to the drive sprocket, but rather are affixed to ratchet mechanisms which in turn drive the drive sprocket in only one direction of rotation. The two pedal arms are linked together by a bellcrank mechanism, so that when one pedal is descending, the other is forced to rise. The ratchet mechanism may be locked to provide for conventional circular pedal operation, if so desired. Pollard has only a conventional Derailleur mechanism having only a finite number of ratios, unlike the infinitesimally adjustable mechanism of the present invention. Also, Pollard does not provide any means of adjusting the position of the pedal swing, due to the fixed length and location of the interconnecting bellcrank. Such pedal swing is incrementally adjustable in the present mechanism. Finally, the Pollard pedal arms pivot about the conventional sprocket hub of the bicycle, while the pivot points for the pedal arms of the present mechanism are located on pivotally adjustable plates for adjusting the pedal arm swing.
U.S. Pat. No. 4,077,648 issued on Mar. 7, 1978 to Man Taik Seul, titled xe2x80x9cBicycle Propulsion And Speed Change Means,xe2x80x9d describes a bicycle drive system incorporating opposite reciprocating pedal arms which pivot about a point on the rear frame essentially above the rear wheel hub. Each of the two pedal arms are connected to a drive wheel by two arms, with the length of the arms being remotely and incrementally adjustable to adjust the effective drive ratio by a series of finite increments. The drive wheel turns a sprocket, which is in turn ratcheted to impart driving force to the drive wheel of the bicycle. Seul does not provide any means of adjusting the swing arc of the pedals to a different position, nor any infinitesimally adjustable ratio means, as in the present drivel mechanism. Moreover, the Seul pedal arms pivot about a fixed point on the frame of the bicycle, unlike the adjustably positionable pedal arm pivot points of the present invention.
U.S. Pat. No. 4,564,206 issued on Jan. 14, 1986 to Larry G. Lenhardt, titled xe2x80x9cPedal Drive,xe2x80x9d describes a mechanism having a relatively large diameter primary sprocket and a smaller diameter secondary sprocket, both rotating at the same speed. A multiple link arrangement connects the two pedal arms with the two sprockets. The resulting pedal travel path is a relatively narrow and elongate kidney-shaped path, generally resembling a reciprocating arc. However, Lenhardt utilizes a conventional Derailleur mechanism having only a finite number of different ratios, unlike the present invention. Also, Lenhardt does not provide any means for altering the travel path of the pedals, as provided in the present invention. Moreover, while the Lenhardt pedal arms do not pivot about the sprocket hub axis, they are not adjustably positionable, as in the present invention.
U.S. Pat. No. 4,574,649 issued on Mar. 11, 1986 to Man T. Seol, titled xe2x80x9cPropulsion And Speed Change Mechanism For Lever Propelled Bicycles,xe2x80x9d describes a rocking pedal action in which each pedal arm is connected to a relatively short length of chain which wraps about a respective sprocket disposed to that side of the drive wheel hub. Each hub contains a cam and roller one way drive device therein. The two chain lengths are connected by a cable, so that when one chain is rotating in a driving direction about its respective sprocket, the opposite chain is being pulled in the opposite direction and free wheels due to the release of the cam and roller mechanism on that side. Seol provides only incremental adjustment of the mechanical ratios of his mechanism, unlike the infinitesimal mechanical ratio adjustment of the present invention. Moreover, the arcuate motion of each pedal arm is fixed and cannot be adjusted using the Seol mechanism, whereas the present mechanism provides such adjustment as desired. The pivot axis of the pedal arms is through the original sprocket hub and is not adjustably positionable, while the pedal arm pivots are adjustably positioned away from the conventional sprocket hub in the present invention.
U.S. Pat. No. 4,961,570 issued on Oct. 9, 1990 to Chester Chang, titled xe2x80x9cExercising Mechanism For Simulating Climbing A Ladder,xe2x80x9d describes a device in which the two opposite pedal arms are pivotally secured at their distal ends to the frame of the machine. Relatively short cranks connecting the arms to a rotary drive wheel result in a reciprocating action of the pedal arms for rotating the wheel. A series of speed increasing gears results in the relatively high speed rotation of an output wheel, with the is mechanical disadvantage provided by the speed increase resulting in a requirement for a relatively large force at each pedal in order to produce sufficient force for rotating the output wheel. Chang does not disclose any means of adjusting the arcuate pedal movement nor of adjusting the effective gear ratios, as provided by the present invention. The Chang pedal arms pivot about a fixed position on the frame of the device and cannot be adjusted, as provided by the present mechanism.
U.S. Pat. No. 5,121,654 issued on Jun. 16, 1992 to Hector G. Fasce, titled xe2x80x9cPropulsion And Transmission Mechanism For Bicycles, Similar Vehicles And Exercise Apparatus,xe2x80x9d describes a mechanism somewhat resembling that of the Seol ""649 U.S. Patent discussed further above. Fasce uses a pair of arcuate chain guides extending from each pedal, with the arcuate path of each guide increasing the length of respective chain travel as the respective pedal is reciprocated through its arc of travel. Springs urge the chain guides and pedals in an upwardly extended direction. The drive hub has two one way clutches, with each clutch freewheeling in the direction of rotation opposite the drive direction. No disclosure is made of any ratio adjusting means or means of adjusting the path of travel of the pedals, which features are provided in the present invention. Moreover, the Fasce pedal arms pivot about the fixed sprocket hub of the bicycle, unlike the variably positionable pedal arm pivots of the present invention.
U.S. Pat. No. 5,351,575 issued on Oct. 4, 1994 to Nathan Overby, titled xe2x80x9cPumping Propulsion System,xe2x80x9d describes a pedal system using a cam and roller one way drive mechanism for each pedal, allowing each pedal to be pumped downwardly to turn the pedal sprocket. A spring is used to draw each pedal upwardly after each down stroke, with a telescoping cylinder provided as a guard over each spring. Overby notes a conventional Derailleur type gear change mechanism at the rear sprocket for his bicycle, but does not describe any form of infinitesimally adjustable ratios or any means of changing the pedal geometry or positioning, as provided by the present invention. The Overby pedal arms pivot about the fixed location of the original sprocket hub, unlike the variably positionable pedal arm pivot points of the present invention.
British Patent Publication No. 610,936 accepted on Oct. 22, 1948 to Mads Kruse, titled xe2x80x9cImprovements In Or Relating To Driving Mechanism For Velocipedes,xe2x80x9d describes a reciprocating pedal arrangement, with the pedals each pulling on a chain or the like which in turn rotates a one way, cam and roller drive sprocket. The xe2x80x9ctension memberxe2x80x9d (chain, etc.) attachment to each of the pedals is adjustable along the length of each pedal, effectively allowing for the adjustment of the xe2x80x9cgear ratioxe2x80x9d of the bicycle. However, no adjustment of the pedal geometry or positioning is provided by Kruse, as is provided by the present mechanism. Also, the pedal arm pivot points of the Kruse mechanism are through the fixed sprocket hub, unlike the variably positionable pedal arm pivot points of the present invention.
British Patent Publication No. 667,655 published on Mar. 5, 1952 to Andre L. Havet, titled xe2x80x9cHub For Bicycles Controlled Through Reciprocating Pedalling And Allowing Forward And Rearward Freewheeling,xe2x80x9d describes a one way, ratcheting type hub mechanism for bicycles. No pedal drive mechanism or adjustment therefor, or adjustable gear ratio means is disclosed by Havet, each of which features is a part of the present invention.
Canadian Patent Publication No. 923,517 issued on Mar. 27, 1973 to George Kay et al., titled xe2x80x9cExercising Machine,xe2x80x9d describes a device having reciprocating foot pedals and cable mechanisms for pulling with the hands and arms. The pedal pivot points are at a fixed location, unlike the adjustable pivot points of the present mechanism, and no adjustable gear ratio means is provided by Kay et al. with their mechanism, as provided in the present invention. Also, Kay et al. do not provide any means of securing a bicycle incorporating an adjustable pedal drive mechanism to their exercise machine, as provided by an embodiment of the present invention.
Finally, European Patent Publication No. 297,579 published on Jan. 4, 1989 to Georg Felkel illustrates a pedal powered drive mechanism for a vehicle. The system appears to use a one way drive (ratchet, etc.) and reciprocates a chain about the drive sprocket by means of a multiple pulley or sprocket system, similar to that used in a block and tackle. No adjustable pedal pivot points are apparent in the Felkel disclosure.
None of the above inventions and patents, either singly or in combination, is seen to describe the instant invention as claimed.
The present invention comprises an adjustable pedal drive mechanism for use with bicycles, exercise machines, and other vehicles and devices which may be pedal powered. A stand for using a bicycle equipped with the present pedal mechanism as an exercise machine, is also disclosed. The present pedal mechanism essentially comprises a pair of plates which are pivotally secured through a lateral passage affixed to the diagonal frame member approximately midway therealong, with a relatively long pedal arm pivotally mounted to each of the plates. Each plate is adjustable relative to the frame of the bicycle, to allow the pedal swing, geometry, or travel arc or range to be adjusted as desired.
A tension member (chain, cable, etc.) is provided on each side of the assembly for independent operation of the two pedal arms, and extends around a pair of sprockets on each pedal arm for greater travel of the tension members for a given stroke of the pedal arms. Each pedal arm includes means for infinitesimally adjusting the contact position of a chain, cable, or the like thereto, for adjusting the effective mechanical ratio of the mechanism. Each of these tension members (chain, cable, etc.) passes about another mechanical ratio adjusting device secured to each of the plates, thence continuing to the rear wheel drive sprocket of the bicycle. An idler pulley is provided for each tension member to reverse its relative direction of motion according to pedal arm movement. The rear wheel sprocket includes two one way clutch mechanisms on each side, thus producing a rotational force to the rear wheel in only a forward rotational direction with both directions of travel of each arcuately reciprocating pedal arm. These one way clutches may be ratchets, cam and roller mechanisms, etc., as desired.
Accordingly, it is a principal object of the invention to provide an improved adjustable pedal drive mechanism for pedal powered devices, including bicycles and exercise machines.
It is another object of the invention to provide an improved pedal mechanism for such devices, which mechanism provides means for collectively adjusting the pivot point and travel path of the pedals of the mechanism as desired.
It is a further object of the invention to provide an improved pedal mechanism including means for infinitesimally adjusting the effective mechanical ratio of the device through a predetermined range of mechanical ratios, as desired.
An additional object of the invention is to provide an improved pedal mechanism including means for independently adjusting the effective ratio of each of the pedals and pedal arms independently of the other, as desired.
Still another object of the invention is to provide an improved pedal mechanism providing for the adjustment of effective ratios as desired when the mechanism is either stopped or in motion.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.